Method and apparatus for replicating the position of intra-osseous implants and abutments relative to analogs thereof

ABSTRACT

The position of intra-osseous implants and abutments to analogs is enabled and enhanced by using the longitudinal axial locked position of a post ( 12   a ) of an implant ( 12 ) having a locking taper in a bore ( 10   a ) of an implant ( 10 ) having a generally matching locking taper as a reference to determine the position of a stop surface ( 14   c ) on impression posts, abutment analog posts and the like received in the bore of an implant and implant analog. In another embodiment the bore ( 16 ) of an implant analog ( 16 ) is provided with a shelf ( 16   c ) located at a position determined by the axial distance of the locked position of the abutment post to prevent over-seating. Controlled retentive resistance and stability of a post is provided by using flats formed in the bore of an implant analog and by forming rings on a post receivable in the bore of an implant or implant analog. One such ring ( 18   c ) is formed with an outer periphery sized and configured to allow bending of the outer peripheral portion in a direction opposite to the direction of insertion in a bore to provide greater retentive resistance than insertion resistance.

RELATED APPLICATIONS

[0001] Benefit is claimed of provisional application No. 60/274,498filed Mar. 9, 2001.

FIELD OF THE INVENTION

[0002] This invention relates generally to medical and dental implantdevices and more particularly to a method for transferring the relativeposition of an intra-osseous implant relative to a laboratory replicatedposition, as in a dental abutment, and for determining the appropriateheight of a dental abutment received in an implant for an aestheticsubmucosal prosthetic margin placement.

BACKGROUND OF THE INVENTION

[0003] Implant systems comprising an implant having a tapered boreadapted to receive therein an abutment post or the like formed with amatching taper for retention of the post in the implant are known. Seefor example U.S. Pat. No. 4,738,623, assigned to the assignee of thepresent invention, the disclosure of which is incorporated herein bythis reference. It is also known to provide such posts, which areintended to be used as impression posts or temporary abutment posts,with a longitudinally extending slot in the end thereof in order to moreeasily remove the posts. Generally, such posts are made of titanium ortitanium alloy due to their biocompatibility characteristics. However,titanium has a major limitation relating to the phenomenon of memory. Itis possible for the diameter of the slotted post to either widen ornarrow over time making the nature of the fit of the post in an abutmentunpredictable. The property of memory can cause an abutment to becomeloose in clinical function and result in an unpredictable degree ofretention.

[0004] There is a need to be able to replicate the position that anabutment would have in an implant in a system using abutment analogs,impression posts and the like made of the same or different materialswhich accurately and reliably correspond to the locked position of apermanent abutment in an intra-osseous implant. Among the factors whichneed to be dealt with in doing this is the existence of hydraulicpressure resisting the seating of a post as well as the need for havingthe post retain its seated position whether gravity is adding a forceagainst seating or toward seating, as in the use in upper teeth versuslower teeth. There is also a need to be able to determine theappropriate height of an abutment which will provide an aestheticsubmucosal prosthetic margin placement.

SUMMARY OF THE INVENTION

[0005] It is an object of the invention to overcome the prior artlimitations noted above. Another object of the invention is theprovision of an impression post and any other post, such as a temporaryabutment post, wherein a clinician will want to remove the post withminimal, predictable effort.

[0006] Briefly, in accordance with one embodiment of the invention, thepost of a member, such as an abutment analog, impression post, implanttransport handler, healing plug and the like, is formed with a radiallyoutwardly extending stop surface such as a shelf having a diameterlarger than the diameter of the bore in a permanent implant and animplant analog and located at a distance from the longitudinal axialposition of a reference location of a head formed on the postessentially equal to the distance from the top end surface of apermanent implant to a corresponding reference location of a head of anabutment with the abutment in a clinically locked position as a resultof being tapped into the implant.

[0007] According to another embodiment, an implant analog is formed witha shelf in the bore of the implant analog located at a distance from themouth of the bore, i.e., the top surface of the implant analog,essentially equal to the distance between the bottom end face of thetapered post of a permanent abutment and the longitudinal axial positionon the tapered post at the top face surface of the permanent implantwith the permanent abutment in the locked position upon receivingclinical tapping insertion force. The shelf prevents a tapered permanentabutment post from over-seating in an implant analog, which isparticularly important when the implant analog is composed of plasticmaterial. According to a feature of the invention, the cylindrical boreof the implant analog can be provided with one or more flats to increasethe retention resistance of a cylindrical post, with or without a taper,received therein as well as to provide an axially extending air passageto relieve or prevent the build up of hydraulic pressure in the closedend of the bore.

[0008] According to a feature of the invention, retentive resistance ofthe post of the abutment analog, impression post, implant transporthandler, healing plug and the like can be increased by forming one ormore circumferential rings about the posts, at least one of the ringshaving an outer diameter larger than the diameter of an implant to forman interference fit and preferably, the at least one ring being flexibleand having a feathered, or otherwise shaped configuration so that uponbeing inserted into the bore of the implant the outer peripheral portionof that ring will bend in a direction opposite to the direction ofinsertion so that upon removal of the post the outer peripheral portionof the ring will have to bend back on itself thereby requiring a greaterremoval force than insertion force.

[0009] According to yet another embodiment of the invention, anelongated probe member having a size to be freely insertable in the boreof an implant is formed with a plurality of axially positioned indexconfigurations, such as circumferential grooves, located in the probemember at selected distances from the free distal end of the probemember corresponding to the position of given reference locations of aclinically seated abutment in the implant. The index configurationsindicate the axial position of a given geometry of the implant bore as areference point so that the appropriate height of an abutment shouldercan be determined to achieve an aesthetic submucosal prosthetic marginplacement.

[0010] Additional objects and features of the invention will be setforth in part in the description which follows and in part will beobvious from the description and drawings. The objects and advantages ofthe invention may be realized and attained by means of theinstrumentalities, combinations and methods particularly pointed out inthe appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate preferred embodimentsof the invention and, together with the description, serve to explainthe objects, advantages and principles of the invention. In thedrawings:

[0012]FIGS. 1a, 1 b are cross sectional views which show a prior artarrangement of an abutment received in the bore of an implant using afirst level of pressure, such as finger pressure and a second level ofpressure, such as by clinically applied tapping, to a locked position inthe bore, respectively; FIGS. 1c, 1 d are similar cross sectional viewswhich show an impression post made in accordance with a first embodimentof the invention, partially received in the bore of an implant and fullyseated therein, respectively; FIGS. 1e, 1 f are similar cross sectionalviews which show an impression post partially received in the bore of animplant analog made in accordance with another embodiment of theinvention and fully seated therein; and FIGS. 1g, 1 h are similar crosssectional views which show an abutment partially received in the bore ofthe implant analog of FIGS. 1e, 1 f and fully seated therein,respectively;

[0013]FIG. 2 is an elevational view of an impression post made inaccordance with another embodiment of the invention and FIG. 2a is anenlarged, broken away portion of FIG. 2; and

[0014]FIG. 3a is a cross section view taken through an intra-osseousmounted implant with an indicator probe made in accordance with theinvention received in the bore of the implant, and FIG. 3b is a viewsimilar to FIG. 3a but showing an abutment received in the bore of theimplant at an apical position related to index configurations of theindicator probe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] With reference to FIGS. 1a, 1 b, a conventional implant 10 isshown having a well or bore 10 a formed with a female locking taper asdisclosed in detail in U.S. Pat. No. 4,738,623 referenced above. Dashedline 2 extends through the top end surface 10 b of the implant shown inFIGS. 1a-1 d and the top end surface 16 b of the implant analogs shownin FIGS. 1e-1 h to be discussed. Dashed lines 4 and 6 show the samereference distances from dashed line 2 in the respective figures. Thepost 12 a of an abutment 12, also provided with a male locking taper, isreceived in bore 10 a at a first apical position relative to the top endsurface 10 b of the implant when a first lower pressure level is used toplace the implant, as by finger pressure. Dashed line 2 aligned with thetop end surface 10 b denotes the axial position of post 12 a in thefirst, partially seated position at a distance d1 measured along thelongitudinal axis of post 12 a and bore 10 a from a reference point ofthe abutment, e.g., the lower end of basal portion 12 c of head 12 b.Abutment 12 is shown with a head 12 b including curved basal portion 12c and shoulder 12 d for receiving thereon a suitable crown or the like,not shown. FIG. 1b includes the same implant and abutment but is shownwith the abutment post after being seated in a second locked position asby tapping the abutment with a clinically applied tapping force. In thefully seated second position the axially measured distance betweendashed line 2 and the same reference point is d2. The change in theapical positions of FIGS. 1a and 1 b has been shown to be 0.006 inch for0.0785 inch diameter post and 0.010 inch for 0.1185 inch diameter postsystems having a locking taper of 1.5 degrees and received in respectivebores of 0.0785 inch and 0.1185 inch having a matching locking taper.The distance d2 is the average distance which was determined by taking agroup of abutments for each diameter post and measuring the individuald2 distance for each abutment upon clinical seating thereof. Thedistance is essentially equal from one abutment to another of a groupwithin manufacturing tolerances and with little or no difference notedfor any variations of clinical insertion force used.

[0016] In accordance with a preferred embodiment of the invention, aradial, outwardly extending shoulder 14 c is formed on post 14 a ofimpression post 14 at an axial distance d2 from a reference point 14 fcorresponding to the reference point 12 f of the abutment shown in FIGS.1a, 1 b. The outer portion of post 14 a is preferably formed with notaper and with a diameter to permit full insertion into the tapered boreof implant 10. The provision of shoulder 14 c, chosen to have an outerdiameter greater than the opening of bore 10 a, results in placement ofhead portion 14 b in essentially the same position in implant 10 as head12 b of abutment 12 in implant 10. A reference configuration, e.g.,circumferential groove 14 g of post 14 can be used to reflect theposition of top end face 12 e of an abutment as noted by dashed line 6.Although an impression post member is shown in the drawings, it will beunderstood that shoulder 14 c can be provided on the post of othermembers such as abutment analogs, healing plugs and the like for receiptin the bore of an implant to obtain the same benefits. Further, itshould be realized that shoulder 14 c can be discontinuous or formed asspaced apart stop surfaces, if desired.

[0017] Referring to FIGS. 1e-1 h, an implant analog 16 made inaccordance with another embodiment of the invention comprises a bodymade of polycarbonate or other suitable plastic such as ultra highmolecular weight polyethylene (UHMW-PE), or a composite, ceramic ormetal and is shown having a bore 16 a of generally the same diameter asbore 10 a of implant 10 however the bore may have a straight bore ifdesired. Bore 16 a is formed with a shelf 16 c formed at a depth oraxial distance from the end face surface 16 b of the implant analogwhich is essentially the same as the distance between dashed lines 2 and4, that is, the axial distance from the top end surface 10 b of implant10 and the bottom end face surface 12 g of abutment 12 when in thesecond, fully seated locked position of FIG. 1b. Placement of shelf 16 cin this position limits travel of an abutment post when inserted intobore 16 a as shown in FIG. 1h and prevents over-seating of an abutmenthaving no shoulder on the post thereof for that purpose. Bore 16 apreferably extends beyond shelf 16 as indicated at 16 d to minimize theeffects of hydraulic pressure build up as a post is inserted in thebore. Preferably the axial distance of post 14 a of impression post 14from shoulder 14 c to end face surface 14 h of the post is selected tobe slightly less than the distance of post 12 a of abutment 12 from anaxial location at dashed line 2 in FIG. 1b indicating a clinicallyseated abutment and end face surface 12 g of the abutment to ensure thatshoulder 14 c limits travel as it engages top end surface 16 b ofimplant analog 16.

[0018] Typically, implants 10 and abutments 12 are composed of titaniumor titanium alloys for biocompatibility while the implant analogs andimpression posts and the like are composed of plastic such aspolycarbonate and ultra high molecular weight polyethylene (UHMW-PE),composites or other suitable materials. This results in a problem insimulating the locking taper of the titanium implants and abutments whenusing a different material for the abutment analog or impression postand when using them without a locking taper. That is, the problem ofachieving the same axial displacement without the same retention and inachieving the same lateral stability of the posts from one female boreto another. According to a modified embodiment of the invention, one ormore flat surfaces 16 e (FIG. 1e) is formed in bore 16 a of implantanalog 16 to form a limited interference with a generally cylindricalpost to increase retentive force and stability of a post receivedtherein. Usually, a plurality of flats, preferably symmetrically spacedabout the periphery of the bore, are formed to provide consistentplacement of a post in the bore of an implant analog relative to thebore of an implant. Such flats also provide an axially extending airpassage to allow air to escape as a post is being inserted in the boreand thereby minimize hydraulic pressure build up.

[0019]FIGS. 2 and 2a show an impression post 18 made in accordance withanother preferred embodiment of the invention which is formed ofsuitable material which in thin configurations has a degree offlexibility, such as some plastic materials, e.g., polycarbonate orultra high molecular weight polyethylene (UHMW-PE), and formed withcircumferentially extending rings or rib like formations 18 b, 18 c onthe portion of post 18 a receivable in the bore of an implant or implantanalog. Post 18 a is cylindrical and can be formed with or without ataper. At least one of the rings is formed to provide an interferencefit. Ring 18 b is used in cooperation with ring 18 c to provide enhancedlateral stability in a bore. Ring 18 c has a slightly larger diameterthan ring 18 b to form an interference fit and is somewhat feathered atits outer periphery or otherwise configured to allow it to be bent in adirection toward or away from the distal free end of the post. When usedin a properly sized bore with or without a locking taper, the materialof ring 18 c is bent upon insertion of the post into such a bore in adirection opposite to the direction of insertion with the outer portionof the ring material being closer to the entrance to the bore than theremainder of the ring. When the post is then removed the outer portionbends back in the opposite direction, that is, in effect, it is foldedback on itself into an ogee type of configuration, due to the limitedspace available, with the base of the ring or rib like formationgradually advancing to the position of the outer portions and finallyassuming a position with the base portion being closer to the entranceof the bore than the outer portion. This reverse bending increases theretentive force for removal, in a manner predictably controlled by thematerial and dimensions of the rings relative to the bore. As a resultof this, the force required to remove the post from such a bore isgreater than the force required to insert the post into the bore. Itwill be understood that ring 18 c can be used by itself, if desired, toprovide a retention resistance greater than an insertion resistance fora post. Likewise, ring 18 b can be used by itself to provide lateralstability as well as retention resistance with the ring having a tightfit or an interference fit, as desired. It will also be understood thatrings as described above can be provided on the posts of other membersreceivable in the well of an implant abutment, e.g., an abutment analog.

[0020] Impression posts were made in accordance with the inventionhaving a nominal post diameter of {fraction (0.113/0.112)} inch for a0.1185 inch diameter bore and provided with first and second spacedapart, circumferentially extending, rings or rib like formations. Thefirst ring, closest to the free end of the post has an outer diameter of{fraction (0.116/0.115)} inch and the second ring has an outer diameterof {fraction (0.119/0.118)} inch. Members having another post size weremade having a nominal post diameter of {fraction (0.073/0.072)} inch fora 0.0785 inch diameter bore, the first ring has a diameter of {fraction(0.076/0.077)} inch and the second ring has a diameter of {fraction(0.079/0.080)}.

[0021] With reference to FIGS. 3a and 3 b, a generally elongatedindicator probe 20 comprises a head portion 20 a formed with an outerperiphery of a size selected to be freely received in the bore of animplant 10 with the distal free end engaging the bottom wall of thebore. Implant 10 is shown in the drawings implanted in the bone of apatient. Horizontally extending, spaced apart index points orconfigurations 20 c are formed on the probe body at locationscorresponding to the axial positions of reference points orconfigurations of an abutment 12 (FIG. 3b) to be clinically seated inthe implant. For example, a longitudinal axial distance d3 from thebottom surface of the bore of implant 10, represented by dashed line 8,to shoulder 12 d of abutment 12, represented by dashed line 9,clinically seated in the second locked position in the implant as shownand described in FIG. 1b, is essentially the same as the axiallongitudinal distance d3 from the distal end surface 20 b to indexconfiguration 20 c of probe 20 when bottomed out in the bore of implant10 of FIG. 3a. Thus probe 20, when seated in the bore of anintra-osseous implant will indicate the axial position of variousgeometries on posts inserted into the implant relative to the height ofsoft tissues overlying the implant by index configurations 20 c-20 g.

[0022] Axial adjustment is essential for the fabrication of integratedabutment crowns, i.e., prefabricated or custom crowns mounted, bonded orfabricated on abutments extra-orally, where the proper anatomicalrelationships and adjustments needed to obtain them are greatly enhancedand facilitated by means of the above described features of theinvention.

[0023] Although the invention has been described with regard to acertain specific embodiment thereof, variations and modifications willbecome apparent to those skilled in the art. For example, although thepost is described as generally cylindrical, it is within the skill ofthe art to use any selected outer configuration, such as elliptical, ifdesired, in conjunction with rib like formations extending around thecircumference as taught by the invention. It is, therefore, theintention that the appended claims be interpreted as broadly as possiblein view of the prior art to include all such variations andmodifications.

What is claimed:
 1. In an implant system having an implant for placement in an osteotomy of a patient, the implant having an inner end for placement in the inner part of the osteotomy and an outer end having a surface, an abutment receiving bore extending through the surface of the outer end of the implant, the bore formed with a locking taper for receipt of the post of an abutment having a generally matching locking taper, the abutment post and the bore having a longitudinal axis and the abutment being seated at a first axial position in the bore upon use of first relatively low insertion pressure and a second further locked axial position in the bore upon use of a second relatively higher clinical insertion force, the bore extending beyond the post of the abutment post in the second locked position, the method of replicating the relative position of an intra-osseous implant and abutment in a laboratory analog comprising the steps of taking an analog implant member and forming a bore through the surface thereof, the bore having generally the same diameter as the bore of the implant, and forming a shelf at a depth selected to be essentially equal to the distance of the second axial position of the bore of the implant from the surface of the outer end of the implant so that a post inserted in the bore of the implant analog member will be limited to a position corresponding to the second locked position of the abutment in the implant.
 2. The method of claim 1 further comprising the step of mitigating the build up of hydraulic pressure in the bore as a post is inserted in the bore of the implant analog member.
 3. The method of claim 2 in which mitigation of the build up of hydraulic pressure is effected by extending the bore beyond the shelf.
 4. The method of claim 1 in which the implant analog member is formed of suitable non-metal material.
 5. The method of claim 1 in which the implant analog member is formed of suitable metallic material.
 6. The method of claim 4 in which the material for the implant analog member is selected from the group consisting of polycarbonate and ultra high molecular weight polyethylene.
 7. The method of claim 1 further comprising the step of increasing retentive resistance and stability of a post received in the bore of the implant analog member.
 8. The method of claim 7 in which retentive resistance and stability of a post received in the bore is increased by forming the bore as a cylinder where at least one flat surface is formed in the bore.
 9. In an implant system having an implant for placement in an osteotomy of a patient, the implant having an inner end for placement in the inner part of the osteotomy and an outer end having a surface, an abutment receiving bore extending through the surface of the outer end of the implant, the bore formed with a locking taper for receipt of the post of an abutment having a generally matching locking taper, the abutment post and the bore having a longitudinal axis and the abutment being seated at a first axial position in the bore upon use of a first relatively low insertion pressure and a second further locked axial position in the bore upon use of a second relatively higher clinical insertion force, the bore extending beyond the post of the abutment post in the second locked position, the method of replicating the relative position of an intra-osseous implant and abutment in a laboratory analog comprising the steps of taking a member formed with a generally cylindrical post having a longitudinal axis and being closely receivable in non-locking relationship in the bore of one of an implant and an implant analog, each having a generally cylindrical post receiving bore of a selected diameter, forming a stop surface on the post extending radially outwardly therefrom beyond the selected diameter to limit insertion of the post into the bore of one of the implant and the implant analog, forming an index configuration on the member at a distance along the longitudinal axis from the stop surface essentially equal to the distance between an index configuration on an implant abutment and the surface of the outer end of the implant when the implant abutment is in the second locked position in the implant.
 10. The method of claim 9 further comprising the step of increasing the retentive resistance and stability of the post received in the bore of an implant and an implant analog.
 11. The method of claim 9 in which retentive resistance of the post received in the bore of an implant analog is increased by forming at least one ring around the circumference of the post having an outer diameter slightly greater than the bore of the implant and the analog implant.
 12. The method of claim 11 in which the said at least one ring has an outer periphery which is configured so that it will bend in a direction opposite to the direction of insertion thereby requiring greater force in removing the post from the bore than is required for inserting the post into the bore.
 13. The method of claim 9 in which the member is formed of non-metal.
 14. In an implant system having an implant for placement in an osteotomy of a patient, the implant having an inner end for placement in the inner part of the osteotomy and an outer end having a surface, an abutment receiving bore extending through the surface of the outer end of the implant, the bore formed with a locking taper for receipt of the post of an abutment having a generally matching locking taper, the abutment post and the bore having a longitudinal axis and the abutment being seated at a first axial position in the bore upon use of first relatively low insertion pressure and a second further locked axial position in the bore upon use of a second relatively higher clinical insertion force, the bore extending beyond the post of the abutment post in the second locked position, the method comprising the step of taking an elongated member having a distal free end and a periphery selected to be freely insertable into the bore of an implant and forming spaced apart indicator configurations on the elongated member at a distance from the distal free end essentially equal to the distance from the bottom of a bore of an implant and a given reference point of an abutment when it is seated in the implant in the second locked position.
 15. A post for placement in the bore of one of an implant and an implant analog comprising a generally cylindrical end portion having a selected diameter and having at least one circumferentially extending ring having a diameter greater than the selected diameter.
 16. A post according to claim 15 comprising first and second spaced apart rings, each having a diameter greater than the selected diameter.
 17. A post according to claim 15 in which the post has a free end and the first ring is closest to the free end of the post and the second ring has a greater diameter than the first ring.
 18. A post according to claim 15 in which the material of the post is selected from the group consisting of polycarbonate and ultra high molecular weight polyethylene.
 19. A post according to claim 15 in which the post is composed of non-metal.
 20. A post according to claim 15 in which the at least one ring has an outer periphery configured so that upon insertion in the bore the outer periphery will bend in a direction opposite to the direction of insertion. 